"'Tiiiiaaaaa!" Luna groaned, following her older sister throughout the castle grounds.
Celestia rolled her eyes and huffed, "We've talked about this, you can't have another day off. You've have too many this month."
She passed through the gate that separated the courtyard to the garden and grinned; she knew that the animals weren't too friendly with Luna and would help to stop her from being annoying.
"But, what about Twilight?" Luna pleaded, brushing up against her sisters coat, "I'm sure she'll be-"
Celestia cut her off, turning to Luna with a serious expression, "Please, I don't need to hear about your 'adventures' with Twilight. Who, might I add, is still my student..." She finished with a raise of her brow and waited for a reply.
Luna smirked, "That's strange... I've seen what you dream about." She then jumped back, barely avoiding the swipe that Celestia threw. "You need to get counseling for what you want to do to her!"
Laughing, she ran from the garden being chased by a fuming Celestia. They ran through the courtyard, barracks and even around Celestia's tower. Twice.
Eventually, Celestia slowed and her expression fell. She stopped outside her chambers and sighed.
Luna stopped beside her and frowned. "'tia, are you okay?"
Celestia shook her head, "I don't think so, lulu." She turned and entered her chambers, the double doors opening for her on their own. She wandered over to her bed and flopped down onto it with a soft 'pomf'.
Luna followed and the doors closed. She went over and knelt besides the bed with her fore-legs next to her sisters. She moved a leg and gently stroked Celestia's side. "'tia, please, tell me what's wrong. Maybe I can help?"
Celestia closed her eyes and inhaled deep, "You are right, sister. I have been having thoughts about Twilight..."
"Oh... I didn't actually know... I was just teasing." Luna looked around awkwardly and let out a small cough.
Celestia shook her head and let out a small chuckle, "It was time to tell you anyway..." she looked down at the silk bedding and felt her lip wobble. "I'm sorry... You are mare-friends... my sister, it isn't right."
Luna closed her eyes and smiled, "For any mortal being, it isn't right," she brought a hoof up and moved some of her sisters hair that had fallen over her face, "but, we are not mortal... And soon, neither will she..."
"If you hate me, just say it. I don't appreciate being played with."
Luna raised a brow, "Sister, You may share her with me... if she allows, of course."
Celestia quickly turned he read to Luna in shock, "Of course she wouldn't!"
"Don't bet on it; I've seen the things she dreams..."
"That's such an immoral use of your powers!"
"Oh? What about when you use yours to spy on her when she's alone?"
Celestia looked away, "That's different, I was making sure she was safe... There's plenty of stuff that could hurt a growing mare..."
"Or that time you used them to watch her sleep..."
Celestia looked around the room for support, "I... I got nothing..." She then turned back to Luna, "That still doesn't excuse you! I may.. Spy, on her, but you see into her desires... For me..."
Her eyes widened, "She wants me..."
"She wants us," Luna deadpanned. "I'm not angry because I know she loves me with everything she has or could have. I don't doubt that for a second and would do anything for her, even let her..." she sighed, "Sleep with you."
"You bit bothered, even a little bit?" Celestia asked, placing a hoof on her sisters.
"I would be lying if I wasn't... But, I do want to see all the fuss is about..."
Celestia looked confused, "What do you mean?"
"Well, I want to know why she wants you... Why our ponies want you...," Her expression turned serious, "Let me fuck you."
"Lulu... You know we can't do that... anymore..." Celestia's face turned bright red, "What if some pony found out or walked in on us?"
Luna's horn glowed and the windows tinted, the doors shut and the walls shone with magic. "There," she said, grinning.
Celestia was speechless.
"Now my dear sister, I want you to kiss me." Luna rose from her kneeling position and leaned in.
Celestia was hesitant at first, but eventually the prospect of having Twilight, even once, spurred her on. She leaned forwards and the two Alicorn's lips met.
Luna turned her head and opened her lips, biting gently on her sisters.
Celestia's breath caught and she kissed back with more passion, pushing her sister back slowly. Luna pushed back with even more and eventually toppled her sister onto her back. She stood over her prize with a grin and said, "Just like old times, eh dear sister."
"Yes," Celestia squeaked, unable to say anything else. She was enjoying this more than she probably should.
"I would let you take charge... you are larger..." Celestia frowned at that, yet Luna continued, "but for old times sake, I'm going to make you scream my name so loud the soundproofing won't work, promise."
Celestia gulped. When her sister promised something, she made it happen. She could only hope Luna wouldn't be too rough with her, she does have to sit on a metal throne.
Celestia's face bloomed. She brought her hooves up to her face and she whispered, "Be gentle..."
Luna leaned down and replied in a whisper, "No."
Gripping Celestia's shoulders, Luna flipped her onto her front and raised her rump high. Taking a hold of her tail, she flicked it to the side, revealing her sisters perfectly untarnished plot-hole and cunt.
"I see that the poets exaggerated."
Celestia closed her eyes and turned away.
"From now on, I'm in charge. You can call me Queen!" Luna shouted, slapping Celestia's rump with her hoof. When she received no reply, she slapped it again. "Lowly peony, your Queen demands you answer!"
"Y-yes..." Celestia shook and tried to turn to look Luna in the eyes, but couldn't bring herself to do it. The memories and guilt of exiling her were too much.
Luna grinned, "Ah, so you're not dumb... You may be of some use to me." She rose up and placed her fore-hooves onto the top of Celestia's rump, holding herself up.
Moving her rump back, she slapped her own cunt into her sisters, making Celestia gasp. "Hmm," she mused, thinking for a second. "Yes... That will be quite nice indeed."
Celestia's ear flicked; the only indication she had heard.
"I have decided that you will be the royal cock-sleeve and your job begins now."
Celestia frowned in confusion, "Cock-sleeve?"
Luna slapped her sisters rump, leaving a rapidly expanding red lump. "No taking. The only time you can open your mouth is to suck!"
Celestia didn't know what her sister was going to do, but it was either going to hurt a lot, or it would be great.
Luna's magic glowed and rapidly changed color to a darker version that eerily matched Nightmare Moon's. She let out a small moan that quickly cascaded into a hearty scream of pleasure.
Celestia felt her instincts try and force her to stop and find out is her sister was in trouble, but that stopped as a strange object started to probe her slit.
She frowned and wiggled eliciting a gasp from her sister. "Lu-Queen... Is-" Celestia started before she herself gasped as she recognized the object.
Luna moved back a forth, teasing Celestia's boiling hot cunt with her newly formed penis. Naturally it wasn't huge, or tiny, it was just right for her and Celestia.
Celestia bit her lip and stifle a moan as the warm appendage dragged across her nether, spreading them open for a second before moving on.
Luna moved her hooves on Celestia's Cutie-marks and began to move them in circles around them, never truly touching them, only making sure her sister could imagine the pleasure.
She looked down at the quivering Celestia and grinned, taking immense pleasure in seeing her sister reduced like that. Not only reduced, but by her, "I'm going to take this slow and savor my new toy.
Celestia could only nod hastily and quickly went back to shaking and moaning. To Luna, she looked like a mortal in heat, "pitiful," she mumbled as she let one of her hooves slide across Celestia's mark, making her let out a howl of a moan.
"You know what you look like?" Luna asked, not expecting a reply. She leaned in closer, knowing that it would make her cock slide in ever so slightly, "You look like a whore in heat, a common pony, some pony we used to use... oh how you've fallen."
Celestia couldn't hear anything other than her own internal need for her sisters dick and simply let her tongue roll out of her mouth.
Luna snickered and pulled on her sister's tail-dock, hard, earning her a yelp of pain, then a satisfying sigh.
Celestia slowly tried moving backwards to spear herself on the meat she so wanted to gobble, but Luna was having none of that and held her in place as she continued to tease her sister.
Soon enough, Celestia couldn't keep herself at bay and spun around, "Dear Faust, FUCK ME, please!"
Luna grinned, "Thought you'd never ask!" She ran her cock along her sisters slit one last time for lubrication and placed her tip at the swollen and sensitive entrance.
Celestia held her breath for what was about to happen and gripped the sheets, nearly ripping them.
Luna glanced at her sisters face and saw a hint of trepidation. She smiled and nodded before pushing in all the way to her base.
The soundproofing on the walls held, barely. The windows shattered violently and Celestia ripped her sheets apart as she shook.
She grunted, feeling the pulsing organ sit comfortably inside her, filling her vagina completely.
Celestia sighed and squirmed about, trying to find anymore of Luna to fit inside her. "You've made this perfect, lulu..." she wrapped her back legs around Luna's body and ground against her, moaning."
Luna lost her breath. It felt like her dick was being massaged and sucked off at the same time and it took all she had not to blow right then and there. Still, she had to hold on and make her sister scream, if only to prove a point that she wasn't the best at everything.
"Mmm, yeah..." Celestia said, closing her eyes and leaning her head back against the bed. She relaxed and allows Luna to the reigns.
Luna started to pull out despite Celestia's protests. Celestia liked feeling full and content with Luna's dick inside her.
She pulled back to the tip and waited a moment before slamming it to the base again, eliciting a coo of pleasure from her sister.
Time after time, Luna trusted and Celestia's moans grew until one powerful thrust caught her g-spot and Celestia let out a loud whinny which caught Luna off guard.
She looked down at Celestia with mirth and smirked, "You really are a whore, ain't you?"
Celestia's face burned with embarrassment and she looked away in shame.
Luna slowly started her thrusts back up and changed her smirk into a love filled expression. "I love you, 'Tia."
Celestia looked back slowly, "Even though..."
"Yes, I still love you, in any way you want..." Luna leaned down and nuzzled Celestia's cheek before pulling back and rubbing noses. "You're my little whore then... and I'm gonna have to make you scream, again."
'Tia lost her embarrassment and smiled, "I love you too..."
Luna grunted and pushed her dick in faster, determined to make her sister whinny again.
Luna circled Celestia's cutie-mark again and rubbed across it repeatedly building up pressure and then releasing in through her body, making it tingle. The tingle passed through her fur until it made it to Celestia's clit where she gasped and let out a loud and feral moan.
Celestia quivered as her orgasm rushed through her, burning up her nerves, leaving them frazzled and extra sensitive.
"OH LUNA!" She screamed, shaking her head from side to side, "MORE!"
Luna obliged and pulled out to her tip before pushing back in harder. Again, Celestia screamed and another wave of pleasure smashed against her mind.
Luna leaned forwards and took a hold of Celestia head, leaning it up so she could stick her tongue into her mouth forcefully. Celestia couldn't feel anything much other than the need to be fucked and so she didn't decline.
Luna ran her tongue around her big sisters mouth, exploring every crevice and enjoying her taste. Celestia felt herself cum again and screamed right into Luna's mouth, pushing her sister to go faster.
Soon enough, Luna felt herself come close and picked up the pace. She slammed her cock into her sister faster and faster until she hilted herself inside her and whinnied, holding her sister tight in a loving embrace.
White, hot, splurges of cum traveled down Luna's cock and lined the walls of Celestia's cunt boiling off from the intense heat that only the Alicorn of the sun could produce inside her. Celestia gobbled it up greedily; her walls milking the cock for everything it had.
Eventually, Luna was spent and pulled her rapidly deflating dick out. She fell to the bed besides her sister and smiled as Celestia fell beside her.
Luna kissed her sister on the cheek then said, "About that day off...?"